Translational Model to Predict Lung and Prostate Distribution of Levofloxacin in Humans

Area of Science:

• Pharmacokinetics and Drug Metabolism
• Antimicrobial Drug Research

Background:

• Levofloxacin (LVX) is a fluoroquinolone antibiotic used for bacterial pneumonia, sinusitis, and prostatitis.
• Efflux transporters are implicated in the tissue distribution of LVX.

Purpose of the Study:

• To characterize LVX tissue exposure using a physiologically based pharmacokinetic (PBPK) model.
• To optimize dosing regimens based on target site pharmacokinetic data.

Main Methods:

• Development and application of a PBPK model in humans.
• Simulation of free LVX concentrations in lung and prostate tissues.
• Assessment of drug penetration and linkage to minimum inhibitory concentrations (MIC).

Main Results:

• The PBPK model accurately reproduced plasma and tissue LVX exposure.
• Efflux transporters affect LVX distribution in prostate but not lung tissue.
• LVX demonstrated good penetration into both lung (Kp,uu=0.79) and prostate (Kp,uu=0.72).

Conclusions:

• LVX exhibits favorable target site exposure in lung and prostate.
• Pathogen susceptibility, not tissue penetration, likely determines treatment effectiveness.
• Findings support refining LVX dosing for improved therapeutic outcomes.